an error in action, calculation, opinion, or judgment caused by poor reasoning, carelessness, insufficient knowledge, etc.

a misunderstanding or misconception.

to regard or identify wrongly as something or someone else

I mistook him for the mayor.

to understand, interpret, or evaluate wrongly; misunderstand; misinterpret.

to be in error. ?

and no mistake

for certain; surely

He's an honorable person, and no mistake.

noun

accuracy , calculation , certainty , correction , correctness , proof , success , truth , understanding

verb

be certain , be sure , comprehend , interpret , perceive , understand

noun

aberration , blooper * , blunder , boo-boo , bungle , confusion , delusion , erratum , false move , false step , fault , faux pas , flub * , fluff * , gaffe , illusion , inaccuracy , inadvertence , lapse , misapplication , misapprehension , miscalculation , misconception , misinterpretation , misjudgment , misprint , misstatement , misstep , muddle , neglect , omission , overestimation , oversight , slight , slip , slip of tongue , slipup * , snafu * , solecism , trip * , typographical error , underestimation , incorrectness , miscue , slip-up , trip , boner , bull , catachresis , error , fallacy , faux pas. impropriety , freudian slip , inadvertency , malapropism , misperception , misunderstanding , paralogism , pratfall , typo

verb

addle , be off the mark , be wrong , blunder , botch * , bungle , confound , confuse , deceive oneself , err , fail , get wrong , goof * , have wrong impression , jumble , lapse , make a mess , misapprehend , miscalculate , misconceive , misconstrue , miscount , misdeem , misinterpret , misjudge , misknow , misread , miss , miss the boat , not know , omit , overestimate , overlook , put foot in , slip * , slip up * , snarl , take for , tangle , underestimate , miscue , slip , slip up , stumble , trip up , mix up , balk , bloomer , blooper , bobble , boner , erratum , error , faux pas , folly , misstep , omission , oversight , slipup